With the advent of digital broadcasting, data broadcasting has also started in Japan, resulting in an environment that provides application services which operate together with television programs (for example, see Patent Literature 1). Meanwhile, in Europe, data broadcasting services such as Hybrid Broadcast Broadband TV (HbbTV) have started, and an environment similar to Japan is in place (for example, see Patent Literature 2).
Herein, an application refers to a computer program written in a language such as HyperText Markup Language (HTML) or Java (registered trademark). Unlike an application that runs on a personal computer or the like, the application herein is able to change behavior in synchronization with signals transmitted by being included in a broadcast wave.
Additionally, the application itself is transmitted by broadcast wave, or acquired by accessing a server on the Internet according to Uniform Resource Locator (URL) information transmitted by being included in a broadcast wave.
Meanwhile, since the Internet is constructed as a basically open environment, there is also a possibility of being provided with malicious applications that change the channel without permission, steal user information, or the like, for example. Accordingly, there is adopted a method that defines different security levels, and restricts the functions of applications not satisfying certain standards.
For example, in the case of data broadcasting in Japan, a state enabling all functions of the receiver is only available on one level of a server domain specified within an application transmitted by broadcast wave, and if the receiver moves to a different domain, the functions cannot be used. In addition, the introduction of hybrid cast services in Japan is now being investigated. With such a service, trusted domains are acquired from information associated with a broadcast wave and managed as a list, and if the receiver is on such a domain, the functions of the receiver become usable.
Also, in the case of HbbTV in Europe, the functions of the receiver only become usable within the scope of an application launched from a signal transmitted by being included in a broadcast wave.